Metalworking lubricant



Patented Apr. 12, 1949 2,467 ,13'7 METALWORKING LUBRICANT Hollis L. Leland, Cranford, N. J.,

Standard Oil Development Company,

ration of Delaware assignor to a corpo- No Drawing. Application December 28', 1945, Serial No. 637,771

8 Claims. 1

The present invention relates to improved metal working oils and methods of making such products, and more particularly the invention is concerned with sulfurized cutting oils which will provide a high load-carrying transparent film of lubricant between the cutting tool and the work being machined.

Cutting fluids, in general, function to dissipate the heat generated by the friction between the cutting tool and the work; improve the quality of the machined surface; lubricate the surfaces in contact between the tool and the work; prevent build-up on the tool or the welding of the work to the tool; wash away the cuttings and provide lubrication between the cuttings and the tool. In order to accomplish all of these functions the cutting fluid must be applied in copious quantities. It is also highly desirable that the workman shall have sufficient visibility of the machined part to determine the quality of the work as the machining operation progresses. There is normally an enormous pressure between the cutting edge of a tool and the metal being machined, and in addition, due to the inherent resiliency of the metal, heavy pressures are maintained between the work and the surface of the tool just under the cutting edge and between the turnings and the surface of the tool just back of the cutting edge. Therefore, another requisite in a cutting fluid is that it be capable of furnishing lubrication under high load conditions.

It has heretofore been recognized that the presence of sulfur and sulfur compounds improves the load-bearing characteristics of an oil, and the load-bearing characteristics of the oil are increased by raising the normal quantity of sulfur found in the oil by the addition of a mineral oil soluble compound or material containing high percentages of sulfur. For most effective use, a cutting oil should contain from 1 to 15% of sulfur. Animal and vegetable oils react much more readily with sulfur than do the mineral lubricating oils, and, therefore, the sulfurized animal and vegetable oils are most commonly used as the means for enhancing the sulfur content of a cutting oil. The sulfurized animal or vegetable oils contain as much as 10 or 20% of sulfur and are produced by reacting either sulfur or a sulfur halide with the animal or vegetable oil by the aid of heat. This reaction results in a discolored oil, generally to the extent of being quite black, and cutting fluids made therefrom actually obscure the metal being fabricated, thus making the required careful inspection ofthe work while mashining quite impossible. Furthermore, it has been found that the sulfurized animal and ve etable oils are not color sively darker in color sulfurized oil such stable, becoming progresduring storage so that a as sperm oil, for instance,

which has been mildly sulfurized so as to produce a sulfurized product relatively light in color, be-

comes dark and opaque upon appreciable time.

The principal standing for any object of the present invention is the production of a sulfurized cutting oil and cutting oil base of high load-carrying ability and capable of producing a transparent film of lubricant. Another object is the production of asulfurized cutting oil base which is stable in color. These and other objects will be apparent to those skilled in the art upon reading the following description.

It has now been found that if the sulfurization of an animal or vegetable oil is conducted in the presence of an alkylated phenol having a boiling point above furized oil of obtained. Sulfurizing the sulfurization temperature, asulimproved color and color stability is procedures in which animal and vegetable oils are sulfurized, are best conducted at temperatures above the melting point of sulfur, which is about 246 F. Therefore, such sulfurization methods are usually conducted at 260 F. to 350 F. desulfurization and the activity of the sulfur. enols having boiling conjunction with sulfurizing processes are 2,6'-di'-tertiary butyl paracrescl and tert.-octyl phenol. It is contemplated that anamine, polyamines, nitro compounds, arcmatic hydroxy compounds, condensation products 1 of amines with aromatic aldehydes or aromatic oxygenated compounds containing more'oxygen than that required of aldehydes, esters, ketones or acids and the chlorine or phosphorus derivatives of amines, 'polyamines, nitro compounds,

aromatic hydroxy compounds, condensation products of amines with aromatic aldehydes and aromatic oxygenated compounds will also improve. the color characteristics of sulfurized cutting oils cr metal working products the formation of such products. The amount of other color-improving compound present during the sulfurizing reaction will and 5 weight per cent based upon the weight of less than 0.1% will the reactants, although usually be found to be su preferred Where alkylated sulfurized metal working when present during alkylated phenol or range between 0.0005

filcient and 0.01% is phenols such as 2,6

di-tertiary butyl para-cresol or tert.-octyl phenol are used.

The fatty oils most generally used as a medium for sulfurization are sperm oil and lard oil, although cottonseed oil, mustard seed oil, peanut oil, coconut oil, olive oil, etc. or mixtures of any of these oils may be used if desired. The sulfurization of the fatty oil may be accomplished in the presence of the fatty oil alone, in which case the sulfurized product is subsequently blended with mineral lubricating oil, or the fatty oil may be sulfurized in the presence of the mineral lubrieating oil which can be an oil having a viscosity at 100 F. in the range of from about 90-500 seconds, an A. P. I. gravity of 2333, and a flash point above 300 F., although it is preferred to use a light Coastal oil having a gravity in the range of from 25 A. P. I. to 31 and a viscosity at 100 F. of from 100-300 seconds. When the fatty oil is sulfurized in the presence of mineral lubricating oil, further blending will depend upon the amount of sulfur in the product and that desired for a particular use. Elemental sulfur and sulfur halides, such as sulfur chloride, are very satisfactory as sulfurizing agents.

In the process of the present invention the usual sulfurizing procedure is followed, which consists in placing the oil to be sulfurized in a reactor equipped with a stirrer and capable of being heated to the desired temperature, adding the sulfur or sulfurizing agent, heating the contents of the reactor with stirring to the desired sulfurization temperature for a time sufiicient to cause the sulfur to remain in solution after the sulfurized oil has cooled to room temperature, except that the sulfurization step is conducted in the presence of an alkylated phenol having a boiling point above the temperature employed during the sulfurization step. The sulfurizatio-n temperature is chosen with a view to the activity desired in the finished product. Within the range of sulfurizing temperatures, the lower temperatures give more corrosive products and conversely the time required for completion of the sulfurization reaction is shorter as the temperatures increases.

The invention will be more readily understood from the following examples which are given for the purposes of illustration.

EXAMPLE 1 CHARGE Sample A Parts by weight Sulfur 12 38 sperm oil 90 Naphthenic lubricating oil 498 2,6 di-tertiary butyl para-cresol 0.06

Sample B Parts by weight Sulfur 12 38 sperm oil 90 Naphthenic lubricating oil 498 Excepting the sulfur, all of the ingredients of Samples A and B were charged to separate iron pots and heated to 320 F. The sulfur was then added and the material in each reactor heated to 320 F. until the sulfur had reacted sufilciently to remain in solution at room temperature. The time required to complete the reaction in each instance was 1 hours. The final products were found to have Robinson color numbers of 2 and 1% respectively.

The Robinson color data were obtained by com- EXAMPLE 2 CHARGE Sample A Parts by weight Sulfur 36 38 sperm oil 264 2,6 di-tertiary butyl para-cresol 0.03

Color, Robinson 1%,.

Sample B Parts by weight Sulfur 36 38 sperm oil 264 Color, Robinson 20% blend in naphthenic oil of Saybolt seconds viscosity at 100 F.

In each sample all of the ingredients exclusive of the sulfur were heated to 320 F. The sulfur was then added and the mixture heated at 320 F. until the sulfur had reacted sufiiciently to remain in solution at room temperature, which required about 2 hours in each instance. The sample containing the alkylated cresol showed a greatly improved Robinson color.

What is claimed is:

1. A transparent sulfurized metal working oil consisting essentially of a mineral lubricating oil and a quantity sufiicient to impart load bearing properties to said oil of a sulfurized fatty oil which has been sulfurized in the presence of 0.0005 to 5,% by weight, based on the total composition, of an alkylated phenol selected from the group consisting of tertiary octyl phenol and 2,6-di-tertiary butyl para-cresol, said metal working oil having an overall sulfur content between 1 and 15% by weight.

2. A transparent sulfurized metal working oil consisting essentially of mineral base lubricating oil containing a quantity, sfiicient to impart load bearing properties to said oil, of a sulfurized sperm oil which has been sulfurized by heating to a temperature of 260 to 350 F. in the presence of 0.0005 to 5% by weight, based on the total composition, of an alkylated phenol selected from the group consisting of tertiary octyl phenol and 2,6-di-tertiary butyl para-cresol, said oil having an overall sulfur content between 1 and 15 by weight.

3. A transparent sulfurized metal working oil consisting essentially of mineral lubricating oil and a quantity suificient to impart load bearing properties to said oil of a sulfurized sperm oil containing 1020% by weight of sulfur which has been sulfurized in the presence of 0.0005 to 5% by weight, based on the total composition, of an alkylated phenol selected from the group consisting of tertiary octyl phenol and 2,6-di-tertiary butyl para-cresol.

4. A transparent sulfurized metal working oil consisting essentially of mineral lubricating oil and a quantity sufficient to impart load bearing properties to said oil of a sulfurized sperm oil containing 10-20 of sulfur, said sulfurized sperm oil resulting from the reaction of sperm oil with sulfur at a temperature of 265-375 F. in the presence of 0.0005 to by weight, based on the total composition, of 2,6-di-tertiary butyl paracresol.

5. The method of making a transparent metal working blending agent which comprises heating -20% by weight of sulfur, 75-90% of a fatty oil and from 0.0005 to 5% by weight, based on the total composition, of alkyl phenol selected from the group consisting of tertiary octyl phenol and 2,6-di-tertiary butyl para-cresol to a temperature in the range of 265-375 F. fora time sufficient to cause said sulfur to remain substantially in solution at room temperature, said alkyl phenol having a boiling point above the temperature of sulfurization.

6. The method of making a transparent metal working blending agent which comprises heating a composition consisting essentially of 36 parts by weight of sulfur, 264 parts by weight of sperm oil and 0.03 part by weight of 2,6-di-tertiary butyl para-cresol to a temperature of 320 F. for a time sufficient to cause the sulfur to remain in solution at room temperature.

7. The method of making a transparent metal working oil which comprises heating a composition consisting essentially of 12 parts by weight of sulfur, 90 parts by weight of sperm oil, 498 parts by weight of mineral lubricating oil and 0.06 part by weight of 2,6-di-tertiary butyl para-cresol to 'a temperature of 320 F. for 1 hours.

8. The method of making a. transparent metal working on which comprises heating 10-20% of sulfur, -90% of sperm oil and 0.0005 to 5% by weight, based on the total composition, of tart.- octyl phenol to a temperature of 320 F. for 1 hours to cause said sulfur to react with and remain substantially in solution.

HOLLIS L. LELAND.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,156,492 Remane Oct. 12, 1915 1,450,463 Thauss Apr. 3, 1923 1,803,933 Cushman May 26, 1931 2,195,510 Cantrell Apr. 2, 1940 2,202,877 Stevens et a1 June 4, 1940 2,227,643 Zimmer Nov. 26, 1940 2,264,896 Bahlke Dec. 2, 1941 2,296,037 Kaufman Sept. 15, 1942 2,320,263 Carlson May 25, 1943 2,357,211 Lincoln Aug. 29, 1944 FOREIGN PATENTS Number Country Date 537,033 Great Britain 1941 

